The modern communications era has brought about a tremendous expansion of wireline and wireless networks. Computer networks, television networks, and telephony networks are experiencing an unprecedented technological expansion, fueled by consumer demand. Wireless and mobile networking technologies have addressed related consumer demands, while providing more flexibility and immediacy of information transfer.
Current and future networking technologies continue to facilitate ease of information transfer and convenience to users. One area in which there is a demand to increase ease of information transfer relates to switching between access points within a network. For example, a wireless local area network (Wireless LAN) typically comprises multiple access points and mobile terminals. Each mobile terminal communicates with an access point using wireless transmissions. The access point is typically attached to some fixed network such as a wired LAN although such fixed network might be implemented in many ways including more wireless links. For purposes of this description, consider the example of an Ethernet LAN.
Data originating from a mobile terminal passes wirelessly to an access point and may then be further transmitted by the access point to a third party device that is accessible through the wired LAN. Similarly data originating from such a third party device, and addressed to the mobile terminal, will be delivered to the access point, which will then transmit the data wirelessly to the mobile terminal. Such a system works reliably so long as the access point and mobile terminal have effective wireless communications.
As stated above, networks often include multiple access points. Additionally, it is often desirable for a mobile terminal to have the ability to switch between access points such as in instances in which the location of the mobile terminal has moved such that the mobile terminal can more effectively communicate with a different access point than the initial access point with which the mobile terminal previously communicated. As such, when a mobile terminal desires to switch from a first access point to a second access point, for example, in which both first and second access points are connected to the same LAN, the mobile terminal may elect to use the second access point for its communication and cease to use the first access point. Such a transition may be accomplished using various signaling methods. Following the transition, data will be sent from the mobile terminal to the second access point for further transmission to the third party device and data arriving from the third party device will be transmitted to the mobile terminal from the second access point.
It is currently common for problems to arise during the transition from the first access point to the second access point. For example, during normal operation, data arriving from the third party device may be delivered to the first access point which does not or cannot transmit such data to the mobile terminal immediately, but, which instead, stores the data until a later, and perhaps more convenient, time. This storage or other delay in transmission by the first access point may cause problems when the mobile terminal transitions to a second access point. In this regard, at the point of transition, the mobile terminal informs the second access point to start forwarding any messages from the third party device so that the second access point will start to accept data from the LAN in preparation for transmission. At this time the mobile terminal will be waiting to receive data from the second access point. However, a problem occurs where the first access point has stored data in preparation for transmission to the mobile terminal, but the mobile terminal transitions to the second access point before the first access point starts to send the data. In such a case the data will not be delivered to the mobile terminal and will instead be lost.
While data lost during a transition between access points can be retransmitted in a manner suitable for some applications, other applications, such as voice over IP and video streaming which are not tolerant to lost data. In conjunction with voice and video data, for example, lost data usually results in aberrations in the sound or picture quality. Thus, a need exists for reducing, if not eliminating, data that would otherwise be lost while transitioning between access points.